// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2012 Chen-Pang He <jdh8@ms63.hinet.net>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_PACKED_TRIANGULAR_MATRIX_VECTOR_H
#define EIGEN_PACKED_TRIANGULAR_MATRIX_VECTOR_H

namespace internal {

template<typename Index, int Mode, typename LhsScalar, bool ConjLhs, typename RhsScalar, bool ConjRhs, int StorageOrder>
struct packed_triangular_matrix_vector_product;

template<typename Index, int Mode, typename LhsScalar, bool ConjLhs, typename RhsScalar, bool ConjRhs>
struct packed_triangular_matrix_vector_product<Index, Mode, LhsScalar, ConjLhs, RhsScalar, ConjRhs, ColMajor>
{
	typedef typename ScalarBinaryOpTraits<LhsScalar, RhsScalar>::ReturnType ResScalar;
	enum
	{
		IsLower = (Mode & Lower) == Lower,
		HasUnitDiag = (Mode & UnitDiag) == UnitDiag,
		HasZeroDiag = (Mode & ZeroDiag) == ZeroDiag
	};
	static void run(Index size, const LhsScalar* lhs, const RhsScalar* rhs, ResScalar* res, ResScalar alpha)
	{
		internal::conj_if<ConjRhs> cj;
		typedef Map<const Matrix<LhsScalar, Dynamic, 1>> LhsMap;
		typedef typename conj_expr_if<ConjLhs, LhsMap>::type ConjLhsType;
		typedef Map<Matrix<ResScalar, Dynamic, 1>> ResMap;

		for (Index i = 0; i < size; ++i) {
			Index s = IsLower && (HasUnitDiag || HasZeroDiag) ? 1 : 0;
			Index r = IsLower ? size - i : i + 1;
			if (EIGEN_IMPLIES(HasUnitDiag || HasZeroDiag, (--r) > 0))
				ResMap(res + (IsLower ? s + i : 0), r) += alpha * cj(rhs[i]) * ConjLhsType(LhsMap(lhs + s, r));
			if (HasUnitDiag)
				res[i] += alpha * cj(rhs[i]);
			lhs += IsLower ? size - i : i + 1;
		}
	};
};

template<typename Index, int Mode, typename LhsScalar, bool ConjLhs, typename RhsScalar, bool ConjRhs>
struct packed_triangular_matrix_vector_product<Index, Mode, LhsScalar, ConjLhs, RhsScalar, ConjRhs, RowMajor>
{
	typedef typename ScalarBinaryOpTraits<LhsScalar, RhsScalar>::ReturnType ResScalar;
	enum
	{
		IsLower = (Mode & Lower) == Lower,
		HasUnitDiag = (Mode & UnitDiag) == UnitDiag,
		HasZeroDiag = (Mode & ZeroDiag) == ZeroDiag
	};
	static void run(Index size, const LhsScalar* lhs, const RhsScalar* rhs, ResScalar* res, ResScalar alpha)
	{
		internal::conj_if<ConjRhs> cj;
		typedef Map<const Matrix<LhsScalar, Dynamic, 1>> LhsMap;
		typedef typename conj_expr_if<ConjLhs, LhsMap>::type ConjLhsType;
		typedef Map<const Matrix<RhsScalar, Dynamic, 1>> RhsMap;
		typedef typename conj_expr_if<ConjRhs, RhsMap>::type ConjRhsType;

		for (Index i = 0; i < size; ++i) {
			Index s = !IsLower && (HasUnitDiag || HasZeroDiag) ? 1 : 0;
			Index r = IsLower ? i + 1 : size - i;
			if (EIGEN_IMPLIES(HasUnitDiag || HasZeroDiag, (--r) > 0))
				res[i] +=
					alpha *
					(ConjLhsType(LhsMap(lhs + s, r)).cwiseProduct(ConjRhsType(RhsMap(rhs + (IsLower ? 0 : s + i), r))))
						.sum();
			if (HasUnitDiag)
				res[i] += alpha * cj(rhs[i]);
			lhs += IsLower ? i + 1 : size - i;
		}
	};
};

} // end namespace internal

#endif // EIGEN_PACKED_TRIANGULAR_MATRIX_VECTOR_H
